docs: def get_model_filepath(self, infodict):
          """Get the path to the homology model using information from the index dictionary for a single model.
  
          Example: use self.get_models(UNIPROT_ID) to get all the models, which returns a list of dictionaries.
              Use one of those dictionaries as input to this function to get the filepath to the model itself.
  
          Args:
              infodict (dict): Information about a model from get_models
  
          Returns:
              str: Path to homology model
  
          """
          u = infodict['uniprot_ac']
  
          original_filename = '{}_{}_{}_{}'.format(infodict['from'], infodict['to'],
                                                   infodict['template'], infodict['coordinate_id'])
          file_path = op.join(self.metadata_dir, u[:2], u[2:4], u[4:6],
                              'swissmodel', '{}.pdb'.format(original_filename))
  
          if op.exists(file_path):
              return file_path
          else:
              log.warning('{}: no file {} found for model'.format(u, file_path))
              return None